Impact Attenuating Pathway and Methods of Making/Use

Abstract

Embodiments of the present disclosure are directed to impact-attenuating pathways that can be easily installed in outdoor areas, such as an outdoor area associated with a senior or assisted living facility. The impact attenuating pathways of the present disclosure provide a natural looking path having impact attenuation properties that can help prevent life threatening injuries. In addition to the impact attenuation properties, the pathway is configured to withstand regular wear from shoes, canes, crutches, and the like. The impact-attenuating pathway comprises a firm base layer, such as concrete; a cushion layer positioned on top of the base layer; and a wear layer positioned on top of the cushion layer.

Claims

1. An impact attenuating pathway comprising: a. a firm base layer, such as concrete; b. a cushion layer positioned on top of the base layer; c. a wear layer positioned on top of the cushion layer.

2. The impact attenuating pathway of claim 1 further comprising a first side edge and a second side edge, each of the first and second side edges being angled less than 70° with respect to an adjacent ground surface.

3. The impact attenuating pathway of claim 2, wherein each of the first and second side edges are angled less than 60° with respect to an adjacent ground surface.

4. The impact attenuating pathway of claim 2, wherein each of the first and second side edges is angled greater than 10° with respect to the adjacent ground surface.

5. The impact attenuating pathway of claim 3, wherein each of the first and second side edges is angled greater than 20° with respect to the adjacent ground surface.

6. The impact attenuating pathway of claim 1, wherein each of the base layer, the cushion layer, and the wear layer comprises a first side edge and a second side edge, each of the side edges being angled less than 70° optionally less than 65°, optionally less than 60° with respect to a ground surface adjacent to the pathway.

7. The impact attenuating pathway of claim 6, wherein each of the side edges is angled greater than 10°, optionally greater than 20°, optionally greater than 30° with respect to the adjacent ground surface.

8. The impact attenuating pathway of claim 1, wherein the top surface of the wear layer is substantially planar with the adjacent ground surface.

9. The impact attenuating pathway of claim 1, wherein the cushion layer has a thickness between an upper surface and a lower surface that is between 1.5 inches and 3 inches.

10. The impact attenuating pathway of claim 1, wherein the wear layer has a thickness between an upper surface and a lower surface that is between 0.4 inches and 1 inch.

11. The impact attenuating pathway of claim 1, wherein the base layer is concrete.

12. The impact attenuating pathway of claim 1, wherein the cushion layer comprises, consists essentially of, or consists of a blend of a. a rubber component; and b. a binder.

13. The impact attenuating pathway of claim 12, wherein the rubber component comprises rubber chunk, tire buffings, or a combination thereof.

14. The impact attenuating pathway of claim 12, wherein the rubber component has a mean Shore A durometer less than 80.

15. The impact attenuating pathway of claim 12, wherein the binder makes up between 4% and 10% of the blend.

16. The impact attenuating pathway of 13, wherein the rubber component is at least 50% rubber chunk.

17. The impact attenuating pathway of claim 1, wherein the wear layer comprises, consists essentially of, or consists of a blend of a. rubber granules; and b. a binder

18. The impact attenuating pathway of claim 17, wherein the rubber granules are sized between 1 and 4 mm.

19. The impact attenuating pathway of claim 17, wherein the rubber granules comprise thermoplastic vulcanizates (TPV) granules.

20. The impact attenuating pathway of claim 17, wherein the binder makes up between 15% and 25% of the wear layer blend.

21. The impact attenuating pathway of claim 1, wherein the pathway is configured to achieve a Head Injury Criterion (HIC) score less than 750 (at each of three temperatures: −6° C., 23° C., and 49° C.), optionally less than 700, optionally less than 650, optionally less than 600, optionally less than 550, at a cushion layer thickness of 2.0 inches or less and a wear layer thickness of 0.75 inches or less, as tested by ASTM F1292-18 at a specified impact height of 4 feet.

22. The impact attenuating pathway of claim 1, wherein the pathway is configured to withstand regular wear from shoes, canes, crutches, and the like over a period of at least 5 years.

23. A method of attenuating the impact of a person falling, the method comprising providing an outdoor area with the impact attenuating pathway of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] A clear conception of the advantages and features of one or more embodiments will become more readily apparent by reference to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings:

[0021] FIG. 1 is a cross-sectional elevation view of an impact attenuating pathway of according to an embodiment of the present disclosure.

[0022] FIG. 2 is a cross-sectional elevation view of an impact attenuating pathway according to an embodiment of the present disclosure, showing each of a base layer, cushion layer, and wear layer.

[0023] FIG. 3 shows an example of a chunk component used in embodiments of the cushion layer described herein.

[0024] FIG. 4 shows an example of a tire buffings component used in embodiments of the cushion layer described herein.

DETAILED DESCRIPTION OF THE INVENTION

[0025] Though developed from similar materials as playground surfaces, the impact attenuating pathways of the present disclosure have been created and designed to operate as pathways upon which users walk, e.g. sidewalks, and in particular pathways for installation and use in senior and assisted living facilities. For instance, embodiments of the impact attenuating pathways are configured both to withstand repeated traffic from mobility devices (e.g. canes, crutches, walkers, wheelchairs, etc.) and to provide a soft landing surface that prevents injuries, and in particular severe head injuries. Embodiments of the impact attenuating pathways are also configured to transition substantially seamlessly into the surrounding environment, such that they do not create sharp edges that might cause one to trip and fall and/or that can be problematic for a user in a wheelchair.

[0026] In some embodiments, the impact attenuating pathway may be configured to provide a degree of impact attenuation performance characterized by a Head Injury Criterion or HIC score. The Head Injury Criterion or HIC score is an empirical measure of impact severity based on published research describing the relationship between the magnitude and duration of impact accelerations and the risk of head trauma. The HIC score of a surface is measured in accordance with the standards set out in ASTM F1292-18 (Rev. 6, Effective Date 2018-1-25), which specifies impact attenuation performance requirements for playground surfaces and surfacing materials. In particular, ASTM F1292-18 provides a means of determining impact attenuation performance using a test method that simulates the impact of a person's head with the surface. Although developed for playground surfaces, the present inventors have determined that the same impact attenuation performance testing can also advantageously be used in the context of the impact attenuating pathways of the present disclosure.

[0027] For example, in some embodiments, the pathway may be capable of achieving a Head Injury Criterion (HIC) score less than 750 (at each of three temperatures: −6° C., 23° C., and 49° C.), alternatively less than 700, alternatively less than 650, alternatively less than 600, alternatively less than 550, at a cushion layer thickness of 2.0 inches or less and a wear layer thickness of 0.75 inches or less, as tested by ASTM F1292-18 at a specified impact height of 4 feet.

[0028] Embodiments of impact attenuating pathways 10 are shown in cross-section in FIGS. 1 and 2. As shown in those figures, embodiments of the present disclosure are directed to an impact attenuating pathway 10 that comprises a firm base layer 11, such as concrete or asphalt; a cushion layer 12 positioned on top of the base layer; and a wear layer 13 positioned on top of the cushion layer. The thicknesses of the various layers may be selected to achieve a desired combination of impact attenuation and wear resistance. In some embodiments, for instance, the cushion layer 12 lay be at least 2.0 inches thick and the wear layer 13 may be at least 0.5 inches thick.

[0029] In some embodiments, the base layer 11 is concrete, desirably a concrete having a compressive strength of at least 3,500 psi, alternatively a concrete having a compressive strength of at least 4,000 psi. The concrete should be thick enough to provide a rigid support onto which the cushion and wear layers can be installed. This base layer 11 provides the impact attenuating pathway with the sturdiness and feel of a conventional walkway such as a sidewalk. The base layer 11 also serves to allow the pathway to withstand the forces that will be placed on it by serving as a high-frequency walkway over an extended period of time.

[0030] In some embodiments, the cushion layer 12 may be a blend of rubber component 21 and a binder 22. The rubber component 21 may desirably have a mean Shore A durometer less than 75. The rubber component 21 may include any of the types of rubber materials used in poured-in-place playground surfaces. For instance, the rubber component may be rubber chunk 23, e.g. such as that shown in FIG. 3, tire buffings 24, e.g. such as that shown in FIG. 4, or any combination thereof. Because rubber chunk 23 is typically softer than tire buffings 24, it may be desirable that the rubber component 21 consist predominantly or entirely of rubber chunk. The rubber chunk 23 may be made up of granules of reclaimed rubber scrap. Accordingly, the rubber chunk 23 may include a mixture of different rubber materials. Those rubber materials may include, for example, styrene butadiene rubber (SBR), ethylene propylene diene monomer rubber (EPDM), nitrile/nitrile butadiene rubbers (NBR), and natural/latex rubbers.

[0031] As shown in FIG. 3, the granules that make up the rubber chunk 23 may be of irregular sizes and shapes. In some embodiments, the granules may be processed so as to provide some degree of size uniformity. For instance, the granules may be run through one or more filters in order to remove granules above a certain size. For example, the granules may all have at least one dimension with a maximum cross-section of less than one inch. In some embodiments, for instance, the granules may be filtered using a ⅝ inch filter. As such, the granules may all have at least one dimension with a maximum cross-section of ⅝ inch or less. In other embodiments, the granules may be filtered using ½ inch filter (producing granules having at least one dimension with a maximum cross-section of ½ inch or less), ⅜ inch filter (producing granules having at least one dimension with a maximum cross-section of ⅜ inch or less), ¾ inch filter (producing granules having at least one dimension with a maximum cross-section of ¾ inch or less), ⅞ inch filter (producing granules having at least one dimension with a maximum cross-section of ⅞ inch or less), or the like.

[0032] As shown in FIG. 4, tire buffings 24 are generally elongated, i.e. fiber-like, strands made up predominantly of styrene butadiene rubber (SBR). These strands are recycled tire rubber, typically obtained from the process of re-capping commercial truck tires. In some embodiments, the strands may have a thickness between about 0.5 mm and about 2.0 mm and a length between about 3.0 mm and about 20.0 mm. The strands may generally have an aspect ratio (length to width) of at least 3, alternatively at least 5, alternatively at least 7.

[0033] The binder 22 may be any suitable polymeric binding material. In many embodiments, the binder 22 may be polyurethane. Notably, in order to provide a firmer surface that is better suited to a pathway configured for use by seniors, the ratio of binder 22 to rubber component 21 may typically be greater than that used in playground surfaces.

[0034] The rubber component 21 and the binder 22 may be blended together to create a pourable cushion layer 12 material. The blending may be performed using conventional equipment, such as a rotating tumbler. Once the components are sufficiently blended, the blend may be poured into a cavity in a conventional manner, such as through the use of a pouring cart or wheel-barrow. The poured blend may then be spread, e.g. through hand troweling, to produce a cushion layer having a substantially consistent thickness and a smooth, even finish. As the binder 22 dries and hardens, the cushion layer 12 becomes set. The thickness of the cushion layer 12 may be selected to provide a desired degree of fall protection, i.e. impact absorption.

[0035] In some embodiments, the wear layer 13 may also be a blend of rubber granules 31 and a binder 32. In some embodiments, for example, the wear layer 13 may comprise thermoplastic vulcanizates, such as those sold by RoseHill Polymers Group under the commercial designation TPV, or another treated rubber, blended with a polyurethane binder. The rubber granules 31 used in the wear layer 13 may generally be smaller and have a greater degree of uniformity than those used in the cushion layer 12. For example, in some embodiments, the rubber granules 31 used in the wear layer may have cross-sections between about 1 mm and about 4 mm, between about 1 mm and about 3.5 mm, etc. The wear layer 13 may also be prepared in any number of desirable colors, such as through the provision of pre-colored granules and the (typically on-site) mixing of those pre-colored granules in a desired ratio.

[0036] The wear layer 13 may be a poured-in-place material that can be blended and then installed by pouring and spreading in much the same manner as the cushion layer 12 described above. The thickness of the wear layer 13 may be selected to provide a desired degree of wear resistance.

[0037] Notably, because the wear layer 13 not only undergoes environmental wear, but also regular impacts from shoes, including high-heeled shoes, and mobility devices such as canes, crutches, walkers, and wheelchairs, the wear layer may desirably be stiffer, stronger, and more durable than a decorative cap layer found in a playground surface.

[0038] Embodiments of the impact attenuating pathway 10 also comprise a smooth transition into the adjacent ground surface 200. Due to being used outdoors, the adjacent ground surface may be natural earth and grass. Alternatively, particularly when used in associated with a garden, the adjacent ground surface may comprise loose fill material 201 such as soil, mulch, gravel, bark, or the like. In either instance, the adjacent material is worn away by the environment over time. It is important that the side edges 101, 102 of the pathway do not provide a sharp edge that could cause one to trip or the like. Accordingly, embodiments of the pathway comprise side edges 101, 102 that provide a smooth transition between the pathway and the adjacent ground surface.

[0039] In some embodiments, for instance, the side edges 101, 102 of at least a portion of the pathway 10, and optionally the side edges of each of the base layer 11, the cushion layer 12, and the wear layer 13, may be angled less than 90° with respect to the adjacent ground surface. Desirably, the side edges 101, 102 of at least a portion of the pathway 10 may be angled less than 70° with respect to the adjacent ground surface 200, alternatively less than 65° with respect to the adjacent ground surface, alternatively less than 60° with respect to the adjacent ground surface. It has presently been found that at angles greater than 60°, and in particular at angles greater than 65° or 70°, with respect to the adjacent ground surface, the transition between the side edges 101, 102 of a pathway 10 and the adjacent ground 200 may lack the requisite smoothness.

[0040] Although the angle need not be limited on the lower end, it may be desirable that the side edges 101, 102 of at least a portion of the pathway 10, and optionally the side edges of each of the base layer 11, the cushion layer 12, and the wear layer 13, be angled greater than 20° with respect to the adjacent ground surface 200. In some embodiments, the side edges 101, 102 may be angled greater than 5°, alternatively greater than 10°, alternatively greater than 20°, alternatively greater than 30° with respect to the adjacent ground surface 200. The lower the angle, the further into the adjacent ground the side edges of the pathway extend. Thus, although the smoothness of the transition to the adjacent ground is improved, lower angles may become undesirable where space is limited and/or where plant life near the pathway is desired, e.g. where the pathway is used in a garden setting.

[0041] It has presently been found that, for most installations, angles between about 20° and about 55° with respect to the adjacent ground surface provide a desirable combination of (i) a sufficiently smooth transition and (ii) a desirable footprint, though angles outside of that range may be preferred where called for by any particular installation. In some embodiments, the side edges 101, 102 of at least a portion of the pathway 10, and optionally the side edges of each of the base layer, the cushion layer, and the wear layer, may be angled between 70° and 10°, alternatively between 65° and 10°, alternatively between 60° and 10°, alternatively between 70° and 15°, alternatively, between 65° and 15°, alternatively between 60° and 15°, alternatively between 70° and 20°, alternatively, between 65° and 20°, alternatively between 60° and 20° with respect to an adjacent ground surface.

[0042] In some embodiments, the upper surface 14 of the pathway, e.g. the upper surface of the wear layer 13, may be substantially planar with the adjacent ground surface 200, i.e. at the same general elevation or raised only slightly above the adjacent ground surface. By angling the side edges 101, 102 of the pathway downward, natural and/or loose fill materials 201 may fill (or at least partially fill) the space above the sloped surface, enhancing the smooth transition to the adjacent ground.

[0043] In some embodiments, the pathway 10 may further comprise a crushed stone layer 15 below the base layer 11. Among other things, the crushed stone layer 15 provides drainage away from the pathway 10.

Example 1

[0044] Tiles having the cushion layer 12 and wear layer 13 composition according to the present disclosure were tested and found to demonstrate exceptional impact attenuation (in addition to providing the wear resistance and, when incorporated onto a base layer 11, the support necessary to operate as a pathway as described herein).

[0045] The tiles, which were 18 inch×18 inch squares consisted of a cushion layer 12 having a thickness of 2.0 inches and a wear layer 13 having a thickness of 0.75 inches, for a total tile thickness of 2.75 inches. The tiles were sent to TUV SUD America Inc. for testing in accordance with the IPEMA Impact Attenuation Test ASTM F1292-18 (Rev. 6, Effective Date 2018-Jan.-25). All surfaces were dry at the time of testing. Three samples were tested at a specified impact height of 4 feet. The testing was performed at three different measured surface temperatures: −6° C. (21.2° F.), 23° C. (73.4° F.), and 49° C. (120.2° F.). The results are shown in the tables below:

TABLE-US-00001 Drop Surface Temp Height HIC 1 −6° C. (21.2° F.) 4 Ft. 490 2 −6° C. (21.2° F.) 4 Ft. 539 3 −6° C. (21.2° F.) 4 Ft. 533 Average (of second and third drops) 536.0

TABLE-US-00002 Drop Surface Temp Height HIC 1 23° C. (73.4° F.) 4 Ft. 499 2 23° C. (73.4° F.) 4 Ft. 539 3 23° C. (73.4° F.) 4 Ft. 547 Average (of second and third drops) 543.0

TABLE-US-00003 Drop Surface Temp Height HIC 1 49° C. (120.2° F.) 4 Ft. 432 2 49° C. (120.2° F.) 4 Ft. 472 3 49° C. (120.2° F.) 4 Ft. 474 Average (of second and third drops) 473.0

[0046] It can be seen that the described embodiments provide unique and novel impact attenuating pathways/sidewalks 10, having a number of advantages over those in the art. While there is shown and described herein certain specific structures embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.